Good EQ Is the Key to Great Mixes

When mixing, you might think of EQ in the same way that you would think of a Hi-Fi system or guitar amp. It’s the same thing, but it is not correct to assume that you should use it in the same way.

Most beginners resort to EQ charts when they first start out. Although useful, these charts are detrimental to long term development.

The best thing to do is to learn the why behind the proper application of EQ and train your ears to recognise different frequencies.

In this tutorial I’ll show you exactly how to do those two things. By the end of this series you will feel comfortable applying equalization to absolutely any instrument or voice.

EQ’s Place In The Mix

When mixing music, there are four main tools that you should focus on. Volume, panning, EQ and compression. Anything else is a distraction at first and should be ignored.

Get comfortable with EQ and compression and you will be able to use more complicated tools such as limiting, reverb and multi-band compression a lot more effectively.

Volume and panning are relatively easy to understand. It’s how loud the instruments are in relation to each other, and where they are placed in the stereo field. Sounds simple, but don’t underestimate the importance of these factors. These are the building blocks of any great mix.

Then there's equalization. This vital process is the main tool that we have as mixers that allows us to shape sounds to our liking. Whereas volume balancing allows us to control the overall level of an instrument or voice, EQ allows use to zoom in to a sound and adjust the volume of the individual frequencies.

With EQ alone you can remove nasty elements, exaggerate pleasing elements, make things sound different and create space in your mix.

The final essential tool, compression, which I'll cover in another tutorial.

Equalization Explained

Every audible sound sits within the frequency range of human hearing.

A high pitched sound, like a drum cymbal or hissing sound, resides in the top end of the spectrum. A low pitched sound, such as a bass guitar or kick drum, resides in the bottom end of the spectrum.

Every instrument has a fundamental frequency but also has higher overtones and harmonics that give it’s character of sound. An organ sounds different to a bass guitar because of the different overtones and harmonics.

With equalization, you can adjust the character and tone of a sound by boosting or cutting these different frequencies.

It’s important to remember that you can’t completely change a sound with equalization. You can’t create new frequencies. You can only remove or exaggerate what’s already there.

You couldn’t make a car sound like a duck. But you could make a Ford Mustang sound a bit more like a Ford Escort.

Master the Frequency Spectrum

First, it visualises where different instruments sit on the frequency spectrum. This gives you a good indication of whether or not your mix will be too busy. If you have too many instruments in the same range the song will start to sound cluttered and muddy.

Second, it allows you to visualise the different frequency ranges and how they sound. The best thing you can do when you start mixing is learn the frequency spectrum. This one small feat will have a huge impact on how quickly you progress as an home recordist, mixer and engineer.

Notice how the spectrum is broken down into Sub Bass, Bass, Midrange, High Mids and High Freqs. These are your five key frequency ranges. Listen to how each of them sound:

Sub bass:

Bass:

Midrange:

High mids:

High freqs:

Learn the numbers for each of these ranges. Once you’ve done that, take a look at the descriptive ranges just above. Terms like Warmth, Fullness/Mud, Edge and Air.

Here’s a table containing the most important frequency ranges:

Rumble

25Hz - 40Hz

Bottom

60Hz - 90Hz

Boom/Punch

100Hz - 170Hz

Warmth

130Hz - 220Hz

Fullness/Mud

250Hz - 450Hz

Honk

450Hz - 1kHz

Tinny

1kHz - 2kHz

Crunch

2kHz - 4kHz

Edginess/Brittleness

3.5kHz - 6kHz

Sibilance (in voice)

4kHz - 10kHz

Definition

6kHz - 10kHz

Piercing

8kHz - 12.5kHz

Air

15kHz - 20kHz

Load up an instrument and experiment with boosting and reducing each of these frequency ranges.

Remember, though, that they are only guidelines to get you started. Once you become more familiar with the different areas of the frequency spectrum, you'll never need to refer to a chart like this.

Here are some examples of different frequency ranges on an electric guitar. Each example included a narrow boost of just over 10dB for some of the frequency ranges in the table above. I used a drastic boost to make the differences obvious.

Over time you'll start to recognise different frequency ranges and everything will become clearer.

Never use EQ charts when mixing. Especially don’t use EQ charts specific to a particular instrument. Doing this will hinder your progress and will prevent you from training your ears. There are several other techniques that you can use instead that will be discussed in the next section.

The Different Types of EQ That You Need to Know

There are a few different ways in which you can adjust the volume of different frequencies.

Filters allow you to cut out everything above or below a certain frequency. A low pass filter will let everything below the set frequency pass through the filter. A high pass filter will do the complete opposite.

High pass filter

Shelves attenuate or boost everything above or below a certain frequency by a set amount. A high shelf set to 10kHz with a boost of +3dB will boost everything above 10kHz by 3dB. A low shelf would do the opposite.

Shelf EQ

Bell curves boost a frequency and its surrounding frequencies at a set point. You can set the frequency, the gain and also the bandwidth/Q. This dictates how wide or narrow the boost is.

Single band bell curves

As well as these three different ways to adjust frequencies, there are also different types of EQ interfaces.

Graphic equalisers consist of lots of bell curve faders across the whole frequency spectrum. They are used mostly for live sound and adjusting speaker systems.

Fixed equalisers consist of a few fixed frequencies. Sometimes they are bell curves, sometimes shelves. These are used in basic analogue mixing desks and aren’t very versatile due to their fixed frequency positions.

Parametric equalisers are what you'll use most for mixing. These allow you to boost or cut any frequency you want using bell curves, filters and shelves.

Parametric EQ in Pro Tools

Semi-parametric equalisers are also very useful for mixing. These look similar to fixed EQs but allow you to change the frequency that you are adjusting. Most analogue modelling EQ plugins use this interface.

An SSL plugin that models an old analogue channel EQ

In part two of this series, I'll show you the seven rules of EQ and a simple four-step process that will make equalising anything easy.